Management improvements have caused a decline in plant species diversity in
traditionally managed haymeadows. The aim of this study was examine the effects and causes
of management improvements on the soil microbialocmmunity with particular emphasis on
the fungal component.
A seasonal study of 3 sites showed that management improvements to haymeadows
consistently reduced soil microbial biomass C, but had no effect on dehydrogenase activity
and basal respiration. Management improvements to these sites also caused a significant
reduction in VAM spore numbers, soil fungal biomass, measured as soil ergosterol content
and the PLFA 18:w6, and a decrease in the fungal:bacteria PLFA ratio. VAM spore numbers
were not correlated with the possibly mycorrhizal NLFA 16:w5.
In the Welsh haymeadow, fungi of the genera Fusarium, Mucor, Absidia,
Cladosporium, Trichodenna, Acremonium, Zygorhynchus and Paecilomyces were
commonly isolated on litter and soil. Commonly isolated fungi had proteolytic and urease
activity, and approximately half had cellulose and lignin decay abilities. Management
improvements induced shifts in the isolation frequency of these fungi, resulting in an increase
in more general resource fungi, capable of growth on both litter and soil. Management
improvements to haymeadows, may also have reduced species diversity of litter fungi.
Agar and microcosm experiments established that changes in fungal community
structure observed in the field could be in response to changes in plant litter inputs and
applications of NPK fertiliser. Pairings of fungi on PDA showed that there was a combative
hierarchy amongst the fungi, but was not able to show if this hierarchy was affected by NPK.
A field experiment found no response of the soil microbial community to short term
applications (2 years) of fertiliser or fungicide.
The findings of this study suggest that management improvements to grasslands will
induce changes in microbial and fungal community structure, this will be discussed.